Abstract: Under the conditions of electricity markets, in order to solve the problems of power flow over-limit of transmission lines within the region, and to fully coordinate the multi-layer resources, an optimal modeling method for multi-layer integrated security correction is proposed. In this method, taking the elimination of the power flow over-limit of transmission equipment in the region as the objective, a calculation model is established for one-time adjustment of four correction modes including power output of units, unit commitment scheme, inter-provincial exchanged power, and transmission plan of DC tie-lines. By setting unit commitment screening factors, the calculation efficiency of unit commitment is improved. Finally, a case of a regional-level power grid is adopted for simulation verification. The results show that the established model can eliminate the power flow over-limit of transmission equipment, and can meet the actual operation requirements of engineering.